Databases
Store, query and manage data reliably: learn SQL, PostgreSQL, MongoDB and database administration with free, step-by-step roadmaps.
About Databases
A database is an organised collection of data that applications can store, search and update quickly and safely. Nearly every app and website depends on one, from online shops and banking systems to social networks and analytics tools.
Relational databases such as PostgreSQL store data in tables and are queried with SQL, the standard language for working with structured data. NoSQL databases such as MongoDB store flexible documents and suit data whose shape changes often. Database administrators keep production systems backed up, fast, secure and available.
Good database work means careful design, well-written queries, sensible indexing and a plan for backups and growth. The roadmaps below take you from your first query to designing and running production databases, whether you want a career in data or just want your own projects to store data properly.
Where to start
A suggested order if you are new to databases. Each step builds on the one before.
Domains
Complete roadmaps for working with databases, from design to administration.
Skills
Query languages and databases you can learn on their own or alongside a domain.
